Navigational Instruments Measuring the Sky

Devices for Measuring Altitude A Quadrant is a simple instrument for measuring Altitude. It uses a plumb line and a protractor-like scale (You made one!) Disadvantages: Hard to use on a ship Not good for the Sun

An Astrolabe is also device for measuring altitude. Its advantage is that it can measure the Sun’s Altitude without looking at it Disadvantage: Hard to use on a ship

A cross staff is a medieval device for measuring altitude on shipboard Advantages: Good on a swaying ship Can be used to measure angles other than with the horizon Disadvantages: Doesn’t Measure small angles well More Human Error

The Kamal was used in the Red and Arabian Sea It measure small angles well Knots where tied when in port to record the latitude so it is a combination instrument and record …no numbers!

Other altitude Instruments A Backstaff improved on the cross staff by allowing the Sun’s altitude to be found without looking at it A Sextant is complex instrument that measures Altitude very accurately